32 chemicals (18 developmental toxicants, 7 neurotoxicants, 5 unknowns, and 3 negative controls) will be evaluated with a battery of assays in zebrafish embryos. The maximum tolerated concentration will be determined with 5 concentrations/compound (0.1-1000 ?M). Cardiotoxicity, behavioral alteration (i.e., neurotoxicity), and hepatotoxicity (n=10-20) following compound exposure will be evaluated conducted in zebrafish embryos.